Algal biotechnology has advanced greatly in the past three decades. Many microalgae are now cultivated to produce bioactive substances. Odontella aurita is a marine diatom industrially cultured in outdoor open ponds a...Algal biotechnology has advanced greatly in the past three decades. Many microalgae are now cultivated to produce bioactive substances. Odontella aurita is a marine diatom industrially cultured in outdoor open ponds and used for human nutrition. For the first time, we have systematically investigated the effects of culture conditions in cylindrical glass columns and fiat-plate photobioreactors, including nutrients （nitrogen, phosphorus, silicon, and sulfur）, light intensity and light path, on O. aurita cell growth and biochemical composition （protein, carbohydrate, β-1,3-glucan, lipids, and ash）. The optimal medium for photoautotrophic cultivation of O. aurita contained 17.65 mmol/L nitrogen, 1.09 mmol/L phosphorus, 0.42 mmol/L silicon, and 24.51 mmol/L sulfur, yielding a maximum biomass production of 6.1-6.8 g/L and 6.7-7.8 g/L under low and high light, respectively. Scale-up experiments were conducted with fiat-plate photobioreactors using different light-paths, indicating that a short light path was more suitable for biomass production of O. aurita. Analyses of biochemical composition showed that protein content decreased while carbohydrate （mainly composed of 15-1,3-glucan） increased remarkably to about 50% of dry weight during the entire culture period. The highest lipid content （19.7% of dry weight） was obtained under 0.11 mmol/L silicon and high light conditions at harvest time. Fatty acid profiles revealed that 80% were Cx4, C^6, and C20, while arachidonic acid and eicosapentaenoic acid （EPA） accounted for 1.6%-5.6% and 9%-20% of total fatty acids, respectively. High biomass production and characteristic biochemical composition profiles make O. aurita a promising microalga for the production ofbioactive components, such as EPA and D-1,3-glucan.展开更多
Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92...Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92.5%）. The parental stock of C. gariepinus showed higher survival value of 96.0% under indoor rearing. The hybrid produced by crossing of ♂H. bidorsalis and ♀C. gariepinus showed higher growth rate in hapa under suspended （14. 1 0 g） and non-suspended condition （14.30 g） in earthen pond at the end of four months rearing. The growth rate under suspended and non-suspended condition were very high and were not significant different from each other. Comparatively, the hybrid of the cross between （♀） H. bidorsalis and （♂） C. gariepinus was better than the other cross under non-suspended condition while the parental strain ofH. bidorsalis was to produce under the suspended condition. The purpose of this is to produce improved fish with fast growing trait and other qualitative characters that could meet the economic target of Nigerian aquaculture, The hybrids have potential as commercial food fish.展开更多
Plant tissue culture continues to be of great interest within the realms of molecular biology, plant breeding and plant health However, different plant cultivars have different culture efficiencies to tissue culture. ...Plant tissue culture continues to be of great interest within the realms of molecular biology, plant breeding and plant health However, different plant cultivars have different culture efficiencies to tissue culture. In this research, the response of two Kenyan sweet potato varieties, KEMB 36 and Tainurey, cultured on a low cost tissue culture medium was evaluated. The low cost medium contained plant nutrients that were obtained from locally available fertilizers. Each conventional Murashige and Skoog （MS） macronutrient was individually substituted with a locally available fertilizer. The conventional source of micronutrients was substituted with Stanes~ Iodized Microfood while sucrose was obtained from table sugar. Performance of the two cultivars was monitored over a period of six weeks. KEMB 36 had a better performance than Tainurey with an average of eight nodes, seven leaves, three roots and height of four centimeters per plantlet indicating genotype-dependent response.展开更多
基金Supported by the National High Technology Research and Development Program of China(863 Program)(Nos.2009AA06440,2013AA065805)the National Basic Research Program of China(973 Program)(No.2011CB2009001)the National Natural Science Foundation of China(No.31170337)
文摘Algal biotechnology has advanced greatly in the past three decades. Many microalgae are now cultivated to produce bioactive substances. Odontella aurita is a marine diatom industrially cultured in outdoor open ponds and used for human nutrition. For the first time, we have systematically investigated the effects of culture conditions in cylindrical glass columns and fiat-plate photobioreactors, including nutrients （nitrogen, phosphorus, silicon, and sulfur）, light intensity and light path, on O. aurita cell growth and biochemical composition （protein, carbohydrate, β-1,3-glucan, lipids, and ash）. The optimal medium for photoautotrophic cultivation of O. aurita contained 17.65 mmol/L nitrogen, 1.09 mmol/L phosphorus, 0.42 mmol/L silicon, and 24.51 mmol/L sulfur, yielding a maximum biomass production of 6.1-6.8 g/L and 6.7-7.8 g/L under low and high light, respectively. Scale-up experiments were conducted with fiat-plate photobioreactors using different light-paths, indicating that a short light path was more suitable for biomass production of O. aurita. Analyses of biochemical composition showed that protein content decreased while carbohydrate （mainly composed of 15-1,3-glucan） increased remarkably to about 50% of dry weight during the entire culture period. The highest lipid content （19.7% of dry weight） was obtained under 0.11 mmol/L silicon and high light conditions at harvest time. Fatty acid profiles revealed that 80% were Cx4, C^6, and C20, while arachidonic acid and eicosapentaenoic acid （EPA） accounted for 1.6%-5.6% and 9%-20% of total fatty acids, respectively. High biomass production and characteristic biochemical composition profiles make O. aurita a promising microalga for the production ofbioactive components, such as EPA and D-1,3-glucan.
文摘Interbreeding of Clarias gariepinus and Heterobranchus bidorsalis was done to produce F1 with fast growing trait using synthetic ovaprim hormone （0.5 ml/kg）. Mean hatching rates were very high （between 72.5% and 92.5%）. The parental stock of C. gariepinus showed higher survival value of 96.0% under indoor rearing. The hybrid produced by crossing of ♂H. bidorsalis and ♀C. gariepinus showed higher growth rate in hapa under suspended （14. 1 0 g） and non-suspended condition （14.30 g） in earthen pond at the end of four months rearing. The growth rate under suspended and non-suspended condition were very high and were not significant different from each other. Comparatively, the hybrid of the cross between （♀） H. bidorsalis and （♂） C. gariepinus was better than the other cross under non-suspended condition while the parental strain ofH. bidorsalis was to produce under the suspended condition. The purpose of this is to produce improved fish with fast growing trait and other qualitative characters that could meet the economic target of Nigerian aquaculture, The hybrids have potential as commercial food fish.
文摘Plant tissue culture continues to be of great interest within the realms of molecular biology, plant breeding and plant health However, different plant cultivars have different culture efficiencies to tissue culture. In this research, the response of two Kenyan sweet potato varieties, KEMB 36 and Tainurey, cultured on a low cost tissue culture medium was evaluated. The low cost medium contained plant nutrients that were obtained from locally available fertilizers. Each conventional Murashige and Skoog （MS） macronutrient was individually substituted with a locally available fertilizer. The conventional source of micronutrients was substituted with Stanes~ Iodized Microfood while sucrose was obtained from table sugar. Performance of the two cultivars was monitored over a period of six weeks. KEMB 36 had a better performance than Tainurey with an average of eight nodes, seven leaves, three roots and height of four centimeters per plantlet indicating genotype-dependent response.
